ftrace: add trace-cmd for ftrace control and config

ftrace: add trace-cmd for ftrace control and config

Rather than manually configuring ftrace, trace-cmd was created
to provide a more user friendly interface to the tracer.

Some examples are:

 # ./trace-cmd record -e all ls /bin

Then to see the information:

 # ./trace-cmd report

To see just a subsystem:

 # ./trace-cmd record -e irq ls /bin

To list the available trace events:

 # ./trace-cmd list -e

You can also trace a single trace point with one of two methods:

 # ./trace-cmd record -e sched:sched_wakeup ls /bin

Or simply:

 # ./trace-cmd record -e sched_wakeup ls /bin

This tool also works with tracers (plugins) as well as events

 # ./trace-cmd list -p

Signed-off-by: Bruce Ashfield <bruce.ashfield@windriver.com>